2 ; Graphics driver for the 640x200x2 mode on the C128 VDC
3 ; Maciej 'YTM/Elysium' Witkowiak <ytm@elysium.pl>
5 ; 2004-04-04, Greg King
8 ; For any smart monkey that will try to optimize this: PLEASE do tests on
9 ; real VDC, not only VICE.
11 ; Only DONE routine contains C128-mode specific stuff, everything else will
12 ; work in C64-mode of C128 (C64 needs full VDC init then).
14 ; With special initialization and CALC we can get 320x200 double-pixel mode.
16 ; Color translation values for BROWN and GRAY3 are obviously wrong, they
17 ; could be replaced by equiv. of ORANGE and GRAY2 but this would give only
18 ; 14 of 16 colors available.
20 ; Register 25 ($19) is said to require different value for VDC v1, but I
21 ; couldn't find what it should be.
23 .include "zeropage.inc"
25 .include "tgi-kernel.inc"
26 .include "tgi-mode.inc"
27 .include "tgi-error.inc"
32 ; ------------------------------------------------------------------------
35 VDC_ADDR_REG = $D600 ; VDC address
36 VDC_DATA_REG = $D601 ; VDC data
38 VDC_DSP_HI = 12 ; registers used
49 ; ------------------------------------------------------------------------
50 ; Header. Includes jump table and constants.
54 ; First part of the header is a structure that has a magic and defines the
55 ; capabilities of the driver
57 .byte $74, $67, $69 ; "tgi"
58 .byte TGI_API_VERSION ; TGI API version number
59 xres: .word 640 ; X resolution
60 yres: .word 200 ; Y resolution
61 .byte 2 ; Number of drawing colors
62 pages: .byte 1 ; Number of screens available
63 .byte 8 ; System font X size
64 .byte 8 ; System font Y size
65 .word $100 ; Aspect ratio
67 ; Next comes the jump table. Currently all entries must be valid and may point
68 ; to an RTS for test versions (function not implemented).
89 .addr 0 ; IRQ entry is unused
91 ; ------------------------------------------------------------------------
94 ; Variables mapped to the zero page segment variables. Some of these are
95 ; used for passing parameters to the driver.
104 TEMP2 = tmp4 ; HORLINE
105 TEMP3 = sreg ; HORLINE
107 ; Absolute variables used in the code
111 SCRBASE: .res 1 ; High byte of screen base
113 ERROR: .res 1 ; Error code
114 PALETTE: .res 2 ; The current palette
116 BITMASK: .res 1 ; $00 = clear, $FF = set pixels
118 OLDCOLOR: .res 1 ; colors before entering gfx mode
125 ; Constants and tables
129 DEFPALETTE: .byte $00, $0f ; White on black
130 PALETTESIZE = * - DEFPALETTE
132 BITTAB: .byte $80,$40,$20,$10,$08,$04,$02,$01
134 BITMASKL: .byte %11111111, %01111111, %00111111, %00011111
135 .byte %00001111, %00000111, %00000011, %00000001
137 BITMASKR: .byte %10000000, %11000000, %11100000, %11110000
138 .byte %11111000, %11111100, %11111110, %11111111
140 ; color translation table (indexed by VIC color)
141 COLTRANS: .byte $00, $0f, $08, $06, $0a, $04, $02, $0c
142 .byte $0d, $0b, $09, $01, $0e, $05, $03, $07
143 ; colors BROWN and GRAY3 are wrong
145 ; VDC initialization table (reg),(val),...,$ff
147 .byte VDC_DSP_HI, 0 ; viewpage 0 as default
149 .byte VDC_HSCROLL, $87
152 SCN80CLR: .byte 27,88,147,27,88,0
156 ; ------------------------------------------------------------------------
157 ; INSTALL routine. Is called after the driver is loaded into memory. May
158 ; initialize anything that has to be done just once. Is probably empty
161 ; Must set an error code: NO
165 ; check for VDC version and update register $19 value
167 ; check for VDC ram size and update number of available screens
169 ldx #VDC_CSET ; determine size of RAM...
173 jsr VDCWriteReg ; turn on 64k
175 jsr settestadr1 ; save original value of test byte
179 lda #$55 ; write $55 here
181 jsr test64k ; read it here and there
182 lda #$aa ; write $aa here
184 jsr test64k ; read it here and there
188 jsr VDCWriteByte ; restore original value of test byte
190 lda ptr1 ; do bytes match?
199 jsr VDCWriteReg ; restore 16/64k flag
200 jmp @endok ; and leave default values for 16k
207 sta SCRBASE ; draw page 0 as default
217 jsr VDCWriteByte ; write $55
219 jsr VDCReadByte ; read here
222 jsr VDCReadByte ; and there
231 ldy #$02 ; test page 2 (here)
234 ldy #$42 ; or page 64+2 (there)
238 ; ------------------------------------------------------------------------
239 ; UNINSTALL routine. Is called before the driver is removed from memory. May
240 ; clean up anything done by INSTALL but is probably empty most of the time.
242 ; Must set an error code: NO
249 ; ------------------------------------------------------------------------
250 ; INIT: Changes an already installed device from text mode to graphics
252 ; Note that INIT/DONE may be called multiple times while the driver
253 ; is loaded, while INSTALL is only called once, so any code that is needed
254 ; to initializes variables and so on must go here. Setting palette and
255 ; clearing the screen is not needed because this is called by the graphics
257 ; The graphics kernel will never call INIT when a graphics mode is already
258 ; active, so there is no need to protect against that.
260 ; Must set an error code: YES
265 ; Initialize variables
270 ; Remeber current color value
275 ; Switch into graphics mode (set view page 0)
278 @L2: ldx InitVDCTab,y
287 ; Done, reset the error code
293 ; ------------------------------------------------------------------------
294 ; DONE: Will be called to switch the graphics device back into text mode.
295 ; The graphics kernel will never call DONE when no graphics mode is active,
296 ; so there is no need to protect against that.
298 ; Must set an error code: NO
302 ; This part is C128-mode specific
303 jsr $e179 ; reload character set and setup VDC
305 lda $d7 ; in 80-columns?
309 jsr $ffd2 ; print \xe,clr,\xe
313 jsr $ffd2 ; print clr
314 @L1: lda #0 ; restore view page
319 jsr VDCWriteReg ; restore color (background)
322 jmp VDCWriteReg ; switch to text screen
324 ; ------------------------------------------------------------------------
325 ; GETERROR: Return the error code in A and clear it.
333 ; ------------------------------------------------------------------------
334 ; CONTROL: Platform/driver specific entry point.
336 ; Must set an error code: YES
340 lda #TGI_ERR_INV_FUNC
344 ; ------------------------------------------------------------------------
345 ; CLEAR: Clears the screen.
347 ; Must set an error code: NO
356 jsr VDCWriteReg ; set fill mode
358 jsr VDCWriteByte ; put 1rst byte (fill value)
366 jmp VDCWriteReg ; 1+62*256+127=16000=(640*256)/8
368 ; ------------------------------------------------------------------------
369 ; SETVIEWPAGE: Set the visible page. Called with the new page in A (0..n).
370 ; The page number is already checked to be valid by the graphics kernel.
372 ; Must set an error code: NO (will only be called if page ok)
383 ; ------------------------------------------------------------------------
384 ; SETDRAWPAGE: Set the drawable page. Called with the new page in A (0..n).
385 ; The page number is already checked to be valid by the graphics kernel.
387 ; Must set an error code: NO (will only be called if page ok)
398 ; ------------------------------------------------------------------------
399 ; SETCOLOR: Set the drawing color (in A). The new color is already checked
400 ; to be in a valid range (0..maxcolor-1).
402 ; Must set an error code: NO (will only be called if color ok)
412 ; ------------------------------------------------------------------------
413 ; SETPALETTE: Set the palette (not available with all drivers/hardware).
414 ; A pointer to the palette is passed in ptr1. Must set an error if palettes
417 ; Must set an error code: YES
422 @L1: lda (ptr1),y ; Copy the palette
423 and #$0F ; Make a valid color
428 ; Get the color entries from the palette
430 ldy PALETTE+1 ; Foreground color
436 ldy PALETTE ; Background color
441 lda #TGI_ERR_OK ; Clear error code
445 ; ------------------------------------------------------------------------
446 ; GETPALETTE: Return the current palette in A/X. Even drivers that cannot
447 ; set the palette should return the default palette here, so there's no
448 ; way for this function to fail.
450 ; Must set an error code: NO
458 ; ------------------------------------------------------------------------
459 ; GETDEFPALETTE: Return the default palette for the driver in A/X. All
460 ; drivers should return something reasonable here, even drivers that don't
461 ; support palettes, otherwise the caller has no way to determine the colors
462 ; of the (not changeable) palette.
464 ; Must set an error code: NO (all drivers must have a default palette)
472 ; ------------------------------------------------------------------------
473 ; SETPIXEL: Draw one pixel at X1/Y1 = ptr1/ptr2 with the current drawing
474 ; color. The coordinates passed to this function are never outside the
475 ; visible screen area, so there is no need for clipping inside this function.
477 ; Must set an error code: NO
481 jsr CALC ; Calculate coordinates
503 ; ------------------------------------------------------------------------
504 ; GETPIXEL: Read the color value of a pixel and return it in A/X. The
505 ; coordinates passed to this function are never outside the visible screen
506 ; area, so there is no need for clipping inside this function.
510 jsr CALC ; Calculate coordinates
512 stx TEMP ; preserve X
524 @L1: tya ; Get color value into A
525 ldx #$00 ; Clear high byte
528 ; ------------------------------------------------------------------------
529 ; BAR: Draw a filled rectangle with the corners X1/Y1, X2/Y2, where
530 ; X1/Y1 = ptr1/ptr2 and X2/Y2 = ptr3/ptr4 using the current drawing color.
531 ; Contrary to most other functions, the graphics kernel will sort and clip
532 ; the coordinates before calling the driver, so on entry the following
533 ; conditions are valid:
536 ; (X1 >= 0) && (X1 < XRES)
537 ; (X2 >= 0) && (X2 < XRES)
538 ; (Y1 >= 0) && (Y1 < YRES)
539 ; (Y2 >= 0) && (Y2 < YRES)
541 ; Must set an error code: NO
549 ; Original code for a horizontal line
556 jsr CALC ; get data for LEFT
557 lda BITMASKL,x ; remember left address and bitmask
568 jsr CALC ; get data for RIGHT
572 pla ; recall data for LEFT
575 sta X1 ; put left address into X1
578 cmp #%11111111 ; if left bit <> 0
580 sta TEMP2 ; do left byte only...
595 inc X1 ; ... and proceed
599 ; do right byte (if Y2=0 ++ADDR and skip)
601 cmp #%11111111 ; if right bit <> 7
603 inc ADDR ; right bit = 7 - the next one is the last
608 @L11: lda ADDR ; do right byte only...
623 @L2: ; do the fill in the middle
624 lda ADDR ; calculate offset in full bytes
627 beq @L3 ; if equal - there are no more bytes
630 lda X1 ; setup for the left side
633 lda BITMASK ; get color
634 jsr VDCWriteByte ; put 1st value
637 beq @L3 ; 1 byte already written
639 stx ADDR ; if there are more bytes - fill them...
642 jsr VDCWriteReg ; setup for fill
645 jsr VDCWriteReg ; ... fill them NOW!
652 ; End of horizontal line code
668 ; ------------------------------------------------------------------------
669 ; TEXTSTYLE: Set the style used when calling OUTTEXT. Text scaling in X and Y
670 ; direction is passend in X/Y, the text direction is passed in A.
672 ; Must set an error code: NO
682 ; ------------------------------------------------------------------------
683 ; OUTTEXT: Output text at X/Y = ptr1/ptr2 using the current color and the
684 ; current text style. The text to output is given as a zero terminated
685 ; string with address in ptr3.
687 ; Must set an error code: NO
693 ; ------------------------------------------------------------------------
694 ; Calculate all variables to plot the pixel at X1/Y1.
695 ;------------------------
697 ;> ADDR - address of card
698 ;> X - bit number (X1 & 7)
712 sta ADDR+1 ; Y*4+Y=Y*5
722 sta ADDR ; Y*5*16=Y*80
735 lda ADDR+1 ; ADDR = Y*80+x/8
762 @L0: bit VDC_ADDR_REG
771 @L0: bit VDC_ADDR_REG
776 ; ------------------------------------------------------------------------
778 .include "../tgi/tgidrv_line.inc"